Container blank, body, and method of forming



' CONTAINER BLANK, BODY, AND METHOD OF FORMING Filed March 17, 1967 Nov. 5, 1968 0 G. SLOUKA ETAL 2 Sheets-Sheet 1 CONTAINER BLANK, BODY, AND METHOD OF FORMING Filed March 17, 1967 D G. SLOUKA ETAL Nov. 5, 1968 2 Sheets-Sheet 2 INVENTORS. DONALD GLSLOUKA 24202921 T. EL\AS A QRNEYS United States Patent 3,409,206 CONTAINER BLANK, BODY, AND METHOD OF FORMING Donald G. Slouka, Glen Ellyn, and Robert T. Elias, Downers Grove, lll., assignors to Continental Can Company, Inc., New York, N.Y., a corporation of New York Filed Mar. 17, 1967, Ser. No. 623,927 14 Claims. (Cl. 229-51) ABSTRACT OF THE DISCLOSURE This disclosure relates to a container blank and its manufacture wherein the blank is provided with a pair of weakening lines in inner and outer surfaces thereof with one of the pair of weakening lines being wholly confined within the area between the other pair of the weakening lines and defining therewith a removable tear strip portion, the blank being formed from fibrous material, and the fibers of the material being in overlapping relationshi and primarily oriented in alignment with the longitudinal axis of the tear strip portion.

Containers of the type to which this invention is directed are relatively well known and are generally constructed by feeding fibrous paperstock material from a roll along a predetermined path. The web is perforated, scored or similarly provided with lines of weakening which define individual tear strips when the web is afterward cut into body blanks. The body blanks are conventionally formed into tubular hollow container bodies which are longitudinally seamed by, for example, butt or lap seams. A closure is thereafter secured to an axial end of each container body, and a packager subsequently charges the containers with a suitable product and closes the remaining still open axial end of each container.

The tear strip of each packaged container generally includes a starting tab which is manually grasped by a consumer and pulled to remove the tear strip from the container body incident to the removal of the packaged product. The tear strip is generally disposed circumferentially about the body but can also be conventionally disposed in a spiral fashion.

Such conventional easy-open type containers are generally acceptable for a large number of consumer goods, both edible and inedible, but two distinct disadvantages are common to most of these type containers. A major disadvantage is the tendency of the tear strip to tear across its width prior to the entire removal thereof from an associated container. This is particularly true if the tear strip is removed with little caution and in a rapid manner, but even under optimum conditions transverse severance of the tear strips has occurred.

A further and related disadvantage of such conventional containers is the problem of wicking i.e., the absorption of liquid into the fibrous material of the container body through the exposed interior (or exterior) cut edges of the weakening lines. If, for example, a relatively moist product is packaged in a container having weakening lines in its interior surface the moisture is readily absorbed into the container body, causing the same to weaken appreciably and in cases of pronounced wicking the absorption of the moisture causes discoloration of the exteriorly decorated container body. They container is therefore rendered undesirable from the standpoint of its strength characteristics as well as estheti-c appearances and consumer appeal. The weakening of the container body in the area of the tear strip also can cause the tear strip to prematurely pop at its starting end if the packaged product expands and/or releases a gaseous 3,409,206 Patented Nov. 5, 1968 medium, as in the case of yeast dough packaged for baking purposes which can release CO Y In keeping with the above it is a primary object'of this invention to provide novel container blanks and bodies which are adapted to be formed into containers of the easy-open type in which tear strips can be consistently completely removed and conventional wicking is completely precluded.

A further object of this invention is to provide a novel container blank adapted to be formed into a tubular container body, the blank being formed of a generally polygonal sheet of fibrous material, a pair of lines of weakening in opposite surfaces of the sheet defining an elongated removable tear strip portion for facilitating the opening of a container body formed from the blank, the pair of weakening lines in one of the surfaces being wholly confined within an area between the other pair of weakening lines, and at least one of the pair of weakening lines being covered by means susbtantially impermeable to liquid media.

Still another object of this invention is to provide a novel blank of the type heretofore defined wherein the fibers of the sheet are disposed in shingle-like overlapping relationship and are primarily oriented in alignment with the longitudinal axis of the tear strip portion whereby the fiber orientation prevents premature transverse severing of the tear strip portion upon the removal thereof from an associated container.

Yet another object of this invention is to provide a novel container body from any one of the blanks heretofore described by forming the sheet to a tubular configuration having contiguous edge portions secured to each other, and the tear strip portion is disposed generally circumferentially about the tubular sheet.

A further object of this invention is to provide a novel container body of the type immediately heretofore set forth wherein the trailing ends of leading fibers are more closely adjacent an inner surface of the tubular sheet than the leading ends of adjacent trailing fibers whereby the shingle-like arrangement of the fibers assures the entire removal of the tear strip portion.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claimed subject matter, and the several views illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a highly schematic perspective view of an apparatus for forming easy-open container blanks in accordance with this invention, and illustrates a web of fibrous material being sequentially scored, coated and severed to form individual blanks.

FIGURE 2 is a highly enlarged fragmentary sectional view taken generally along line 22 of FIGURE 1, and illustrates opposed scoring rolls forming a pair of score lines in opposite surfaces of the web.

FIGURE 3 is a highly enlarged fragmentary sectional view taken generally along line 33 of FIGURE 1, and illustrates liquid impervious means covering the opposite surfaces of the web.

FIGURE 4 is a highly enlarged fragmentary sectional view taken generally along line 44 of FIGURE 1, and illustrates the shingle-like overlapping relationship of the fibers and the orientation thereof relative to the machine direction of the web.

FIGURE 7 is a top perspective view of a fully assembled and charged container, and illustrates the tear strip portion thereof adjacent an upper closure of the container.

FIGURE 8 is a fragmentary top perspective view of the container of FIGURE 7, and illustrates the manner in which the tear strip portion is manually removed.

FIGURE 9 is a highly enlarged fragmentary sectional view taken generally along line 99 of FIGURE 7, and illustrates the details of the removable tear strip portion.

FIGURE 10 is a highly enlarged sectional view taken generally along line 1010 of FIGURE 8, and illustrates the manner in which the body wall is severed upon the removal of the tear strip portion.

FIGURE 11 is a highly enlarged sectional view taken generally along line 1111 of FIGURE 7, and illustrates the shingle-like orientation of'the fibers relative to the direction of removal of the tear strip portion.

FIGURE 12 is a highly enlarged sectional view taken through another container body generally along a line identical to the line 11-11 of FIGURE 7, and illustrates the orientation of the fibers when the body blank is folded to a tubular configuration in a direction opposite to that of the body of FIGURES 6 through 11.

This invention will be best understood by first referring to one aspect of a typical paper-making operation which directly affects a major feature of the invention.

Paper-making proper from prepared pulp stock, whether of wood, straw, rags or other raw materials, may be said to begin with the operation technically known as beating wherein the pulp is beaten in water to produce a slurry from which a paper web is formed on a paper machine wire. The wire receives the stock in a desired thickness through a slice of the head stock, and as the stock is conveyed toward the couch rolls the water flows from the wire by gravity and/or suction. During the movement of the pulp with the wire the fibers tend to align themselves in the machine direction due to the combining effect of the wire on the fibers. That is, any fibers which leave the slice in a position other than horizontal tend to be pulled at their lower ends into a position generally parallel to the wire direction because of the greater velocity of the water near the wire. In most cases this results in a marked shingle-like overlapped alignment of the fibers on the wire side of the sheet which progressively lessens toward the felt side. In general, a higher ratio of wire speed to stock velocity means that a higher proportion of the fibers will be drawn into the machine direction i.e., a relatively low head of stock in the head box and a relatively high wire speed, Under these conditions there is therefore both vertical and horizontal fiber orientation caused by the combined effects of the speed of movement of the stock and the ends of the fibers being pulled toward the wire by gravity and/ or suction.

The sheet then passes between couch rolls which press out most of the remaining moisture and impart sufitcient consistency to the paper to enable it to leave the wire. The paper is next carried by means of endless felts between press rolls to obliterate the impression of the wire from the underside of the now continuous web. The web of paper is finally dried by passing over a series of hollow steam-heated drying cylinders and reeled into rolls.

One such roll of fibrous paperstock material is illustrated in FIGURE 1 of the drawings, and is generally designated by the reference numeral 15. A web 16 is conveyed from left-to-right by a pair of feed rolls 17, 18 driven by conventional driving means (not shown).

The web 16 includes an upper surface 20 (FIGURES 1 and 4) and a lower surface 21. The upper surface 20 is the wire surface i.e., that surface of the web 16 which was more closely adjacent the Fourdrinier wire during the manufacture of the web, while the surface 21 is the felt surface i.e., that surface against which endless felts are pressed during the pressing operation heretofore described. The machine direction of the web 20 during its formation upon and movement with the Fourdrinier wire is from right-to-left as viewed in FIGURE 1 of the drawings, as indicated by the double-headed arrows in FIGURES l and 4.

Referring particularly to FIGURE 4 of the drawings, the web 16 is formed of numerous fibers, generally designated by the reference numeral 22, which are shown highly magnified in this figure. Three fibers 23, 24 and 25 are illustrated in vertically overlapped relationship to impart a generally shingle-like arrangement to these as well as the numerous other fibers 22 of the web 16. As related to the machine direction (double-headed arrow in FIGURE 4) a trailing end 26 of the leading fiber 23 is more closely adjacent the surface 20 of the web than a trailing end 27 of the next adjacent trailing fiber 24. The trailing end 27 of the fiber 24 is similarly more closely adjacent the surface 21 than a trailing end 28 of the adjacent trailing fiber 25. This arrangement or disposition of the fibers 23 through 25 is merely exemplary of the similar shingle-like pattern formed by like partial overlapping of the remaining fibers 22 which serves a function to be described more fully hereafter.

The web 16 is drawn by the feed rolls 17, 18 through the bight of scoring rollers 30, 31 positioned respectively above and below the web 16, as viewed in FIGURES 1 and 2 of the drawings. The scoring rollers 30, 31 each include a pair of respective circular cutting edges 32, 32 and 33, 33. During the rotation of rollers 30, 31 in opposite directions, as indicated by the associated headed unnumbered arrows in FIGURE 1, the cutting edges 32 form generally V-shaped lines of weakening or score lines 35, 36 in the upper surface 20 of the web 16 while the cutting edges 33 similarly form lines of weakening or score lines 37, 38 of an inverted V-shaped configuration in the lower surface 21 of the web 16. The depth D of the score lines 35, 36 is approximately three-quarters of the thickness of the web 16, as is the depth D of the score lines 37, 38. The score lines 35 through 38 are also in parallel relationship with each other and with the generally linear direction of orientation of the individual fibers 22. The score lines 37, 38 are also disposed wholly inwardly of the area set off between the score lines 35, 36, as is best illustrated in FIGURES 2 and 3 of the drawings.

After the score lines 35 through 38 have been formed in the respective surfaces 20, 21 of the web 16 the surfaces 20, 21 are covered with coverings or layers 40, 41 of fluid impermeable material such as, for example, polyethylene or similar copolymeric thermoplastic material. The coverings 40, 41 are preferably laminated upon the surfaces 20, 21, respectively, by conventional laminating or extruding heads 42, 43. The raw edges of the score lines 35 through 38 are thereby prevented from absorbing moisture either from a packaged product or atmosphere, as will be more apparent hereafter. If desired, the coverings 40, 41 can be aluminum or similar webs of impermeable material adhesively secured to the surfaces in a conventional manner.

After the layers 40, 41 have solidified the web 16 is transversely severed by conventional, reciprocal cutting and notching means 45. The means 45 includes a lower transverse cutting edge (unnumbered) and a pair of generally triangularly shaped notch-forming cutting blades 46, 47 which are in alignment with the score lines 35, 36, respectively. An edge 58 of each polygonal sheet material blank, generally designated by the reference character 50, cut from the web 16 is therefore provided with a pair of V-shaped notches 51, 52 between which is a projecting tab 53 of a removable tear strip portion 54. The tear strip portion 54 is relatively elongated and ends at a terminal edge 59 remote from the notches 51, 52.

The blank is thereafter formed by conventional means to a generally tubular configuration to form a container body 55 (FIGURE 6). A longitudinal lap seam 56 secures the transverse edge portions 58, 59 of the now tubular blank 50 to each other as by, for example, heatsealing or other conventional adhesive securing means. If desired the inner surface of the tab 53 can be provided with a coating of conventional resist material which prevents the tab from adhering to the underlying surface of the body thereby facilitating the manual grasping of the tab incident to the removal of the tear strip portion.

Conventional identical lower and upper closures 60, 61 are thereafter secured to the container body 55 in a conventional manner to form an easy-opening container 65 (FIGURE 7). The lower closure 60 is preferably heatsealed or otherwise secured to the lower axial end (unnumbered) of the container body 55 by the manufacturer while the upper closure 61 is secured in position by a packager only after the container 65 is charged with a suitable product.

Reference is now made to FIGURE 11 of the drawings which illustrates the relationship of the fibers 22 to both the machine direction of the web (unnumbered doubleheaded arrow) and the direction of removal of the tear strip (unnumbered single-headed arrow). The fibers 23,

24 and 25 of FIGURE 4 have been reproduced in FIG- URE 11 and it is to be noted that the orientation of the fibers relative to the machine direction is opposite to the orientation of the fibers with respect to the direction of removal of the tear strip portion. That is, the fiber 23 leads the fiber 24 and the trailing portion (unnumbered) of the fiber 25 is more closely adjacent the surface 21 than the trailing end of the adjacent trailing fiber 24. When the tab 53 is gripped and pulled in the direction of the singleheaded arrow in FIGURE 11 the orientation of the fibers and the partially overlapped relationship thereof relative to the direction of removal permits the entire pull tab portion 54 to be removed as the pull is continued in a clockwise direction. The effect of the orientation of the fibers and the overlapping thereof is such that the leading ends of the trailing fibers continually act against the trailing ends of adjacent leading fibers to permit the continuous uninterrupted removal of the tear strip portion. This is analogous to imagining gripping the lowest shingle of a roof and pulling the shingle upwardly toward the ridge whereby, except for the staggered nature of the shingles, a straight continuous line of the shingles (corresponding to the fibers 22) would be raised upwardly. An opposite pull on the same lowest shingle in a downward direction would remove but the lowest shingle and prevent any movement of adjacent shingles toward the ridge. Thus, from the standpoint of the direction of tear so long as the leading ends of leading fibers are more closely adjacent the inner surface 21 of the container body than the leading ends of adjacent trailing fibers a smooth uninterrupted continuous removal of the tear strip portion 54 is assured.

In the embodiment of the invention thus far described, the container body 55 was described as being formed with the wire side 20 and its associated coating 40 forming an exterior surface of the body while the felt side 21 formed an interior surface thereof. However, in accordance with this invention it is also possible to form a container body in which the wire side 20 is the inner surface of the body and the felt side 21 is the outer surface. Assuming, for example, that the notches 51, 52 are formed in the opposite edge of the blank 50 and this opposite edge is placed in exterior lapping engagement as shown in FIGURE 12, the fibers 23, 24 and 25, as well as the remaining fibers 22, would be disposed in the manner illustrated in FIGURE 12. The direction of tear and the machine direction are again indicated by the single-headed and double-headed arrows, respectively, in FIGURE 12, and it will be noted that the shingle-like orientation and overlapping arrangement of the fibers 22 assure the continuous removal of the tear strip when the same is removed in the direction of the single-headed arrow in this figure.

It is to be particularly noted that if the overlapping relationship of the edge portions were reversed and an attempt was made to remove the tear strip portion by pulling in a direction opposite to the single-headed arrows,

complete removal of the tear strip portions would be virtually impossible because of the tendency of the fibers to shear or separate from each other. That is, assuming the edge portion of the container body containing the fibers 23, 24 and 25 was pulled in the direction of the unnumbered broken arrow in FIGURE 12, the fiber 23 would tend to pull away from the adjacent fiber 24 along the shear line AA. Succeeding fibers would similarly tend to shear away from adjacent fibers and the overall effect would be the inability of the tear strip portion to be completely removed from the container body. In general, any

'tear with the felt side up made in the machine direction will be short but a tear in the same direction with the wire side up would be long, while the opposite would be true of tears against the machine direction. That is, with the felt side up and tearing against the machine direction the tears would be long but with the wire side up the tears would be short.

In addition to constructing the tear strips parallel to the orientationof the fibers (with the grain) it has also been observed that the shingle-like overlapping arrangement of the fibers in the direction of machine travel may not necessarily be perfectly parallel to the direction of travel. Rather, it is possiblefor the fibers to cant from the wire side upwardly toward the felt side to either side of a vertical plane depending upon, for example, a slight tilting of the Fourdrinier wire relative to the horizontal. If the wire were tilted downwardly to the right as viewed in the machine direction the fibers of the stock would similarly tend to tilt to the right while an opposite inclination of the wire would result in an opposite direction of inclination of the fibers relative to the vertical. This results in a similar shingle-like overlapping of fiber groups toward either of the opposite edges of the paper during its formation. This unobvious observation makes it possible to construct a container blank having a tear strip portion adapted for removal against the grain i.e., transverse to the machine direction.

Tests have been conducted to determine the behavior of cross grain tearing by positioning several (15) sheets with the wire side up and the direction of machine travel pointed toward the tester. All 15 tears from right-to-left ran longer than tears from left-to-right indicating that the inclination of the groups of fibers was from left-to-right from the felt side to the wire side with the upper ends of leftmost groups of lower fibers overlapping the lower end of adjacent lower ends of rightmost fiber groups. With the felt side of the tested samples up and the machine direction still toward the tester, all 15 right-to-left tears were againlonger, indicating that the orientation of fibers and groups of fibers in both vertical and horizontal planes can be regulated to obtain longer tears than heretofore provided by known conventional fibrous containers.

It is also pointed out that in the case of forming paper on cylinder machines the same directionalism encountered on Fourdrinier machines is even more extreme because of the greater differences in velocities of the cylinder and the pulp stock. As soon as the fibers strike the moving wire face of the cylinder mold the motion drags the fibers with the mold lining up the fibers in the machine direction in the shingle-like fashion heretofore noted. Therefore, the invention is applicable to either of the two predpminant processes of forming paperstock sheet materia While preferred forms and arrangement of parts have been shown in illustrating the invention, it is to be clearly understood that various changes in details and arrangement of parts may be made without departing from the spirit and scope of the invention as defined in the appended claimed subject matter.

We claim:

1. A blank adapted to be formed into a tubular container body comprising a generally polygonal sheet of fibrous material having opposite surfaces, means defining an elongated removable tear strip portion of said sheet for facilitating the opening of a container formed from the blank, and fibers of said sheet being disposed in overlapping relationship and primarily oriented in alignment with the longitudinal axis of the tear strip portion.

2. The blank as defined in claim 1 wherein said sheet is of a tubular configuration and includes secured contiguous edge portions, and said tear strip portion is disposed generally circumferentially about said sheet.

3. The blank as defined in claim 1 wherein said sheet is of a tubular configuration and includes secured contiguous edge portions, and the trailing ends of leading fibers are more closely adjacent an inner surface of the tubular sheet than the leading ends of adjacent trailing fibers whereby the fibers are arranged in a shingle-like pattern which assures the entire removal of the tear strip portion.

4. The blank as defined in claim 3 wherein said defining means include lines of weakening, and said weakening lines are disposed generally circumferentially about said sheet.

5. The blank as defined in claim 3 wherein said defining means include lines of weakening, said weakening lines are disposed generally circumferentially about said sheet, and said weakening lines are covered by means substantially impermeable to fluid.

6. The blank as defined in claim 3 wherein said defining means include at least a pair of lines of weakening in inner and outer surfaces of said sheet, and the pair of lines of weakening in said inner surface are wholly confined within an area between the other pair of weakening lines in said outer surface.

7. The blank as defined in claim 6 wherein at least one of said pair of weakening lines is covered by means substantially impermeable to fluid.

8. A method of forming a container body blank comprising the steps of providing a sheet of fibrous material in which the fibers are disposed in shingle-like overlapping relationship and are primarily oriented in a single direction, and forming an elongated removable tear strip portion in the sheet having a longitudinal axis in substantial alignment with the direction of orientation of the fibers.

9. The method as defined in claim 8 including the step of forming the blank into a tubular container body in which trailing ends of leading fibers are more closely adjacent an inner surface than the leading ends of adjacent trailing fibers relative to the direction of removal of the tear strip portion thereby assuring the entire removal of the latter portion from a container constructed from said body.

10. The method as defined in claim 8 wherein the tear strip portion is formed by forming a pair of lines of weakening in each surface of the sheet with the pair of weakening lines in one of the surfaces being wholly confined within an area between the other pair of weakening lines.

11. The method as defined in' claim 8 comprising the step of applying fluid impermeable means upon the inner surface of the blank.

12. The method as defined in claim 9 wherein the tear strip portion is formed by forming a pair of linesof weakening in each surface of the sheet with the pair of weakening lines in one of the surfaces being wholly confined within an area between the other pair of weakening lines.

13. The blank as defined in claim 1 wherein themeans defining said elongated removable tear strip portion includes at least a single score line, and said score line is coated with a layer of liquid impermeable material.

14. The blank as defined in claim 1 wherein said defining means includes at least a pair of lines of weakening in each of said surfaces, and the pair of lines of weakening in one of the surfaces is wholly confined within an area between the other pair of the lines of weakening.

References Cited UNITED STATES PATENTS 2,608,341 8/ 1952 Eckman 229-5 1 3,014,630 12/1961 Whelan et al 22951 3,142,433 7/1964 Balocca 229-51 3,175,752 3/1965 Stabenow 22966 DAVID M. BOCKENEK, Primary Examiner. 

